I spoke to the carb guy re: the 350 I am having built for my Apollo. One of his questions relates to my convertor. When I spoke to convertor guy, he wants to know my tire and gear combo. This all makes sense but I need help. My intention was to put a 373 gear in the stock 10 bolt and go with a tasteful looking street tire. Well, I'm going to try my hand at bracket racing as well so what do I do? The engine guy says go towards a 308 gear for engine life. This seems awfully conservative to me. Can I fool with the tire diameter to provide better off-the-line performance on the strip and move up/down in size for street use? What types of info can I share with you guys to help you help me? Thanks a bunch. :TU:
Your engine guy seems pretty conservative to build a bracket racing engine! Go for the 3.73 gears, you will probably need the revs to get that Apollo launched. Unless you plan on a lot of highway driving 3.08 seems too conservative.
Hey Dave, I think I have a tool that might help tremendously. Go to this website and calculate anything you ever wanted to know. It is especially good for determining what RPM's you'll be running with any gear ratio and tire size and tranny. I've double checked these calc's by hand and the website is dead-on. Hope this helps. http://www.thirdgen.org/newdesign/tech/calculations.shtml Good luck! Matt
The key is everything must compliment one another. 3.08's are to small with a small block unless you have to drive the car as a driver. Stall speed must be matched with cam size and gear as well. As for tire size, the smaller the tire the deeper it makes your gearing. Good suggestions can't be made without some specs. If you really want to get it going in a hurry try a 10" 2800-3200 RPM stall with 3.73 gears and a 27" tire.
Seperate and Distinct Guys: Thanks very much for your replies. The more I investigate the more I understand street/strip to be mutually exclusive. I will go with the more aggressive gear and see where that leads me. I can always bring the gear down (numerically) if I am unhappy. The cam specs as read to me are: Adv. Duration of 288 w/ 112 lobe center Duration @ .050 is 231 intake and exhaust 501 lift (I hope I got all this right) Another board member suggested a 28 inch tire for my application. I have not put a tape measure on the car yet, but I'll presume this to be the way I will go. I also have to consider the ratio availability of the 10 bolt currently in the car. I am not too sure how to identify the rear end (among the 10 bolt family) It is the stock unit with what I believe to be 273 and limited slip. My original mission statement was to model my little Buick after a LT-1 Nova or early Z-28. Obviously the Buick and Chevy motors are apples and oranges but the concept of a hot small block in a light unibody car interests me. I believe the L-T1 cars often had 3:73 gears. However, since Buicks don't rev like Chevys, maybe my engine builder is rightfully concerned with the higher RPM on street. I invite/encourage all constructive criticism of my project's vision. You may save me some $$ by pointing out flawed thinking. Thanks David :TU:
That is good size cam for what you are looking for. I would take a real long look at a 10" convertor. I just had to cheange convertors in my dads Vette because the one I originally bought was to tight for the cam. Keep in mind that advertised stall speed is not always an indication of how loose a covertor is. Obviusly a Chevy can rev higher than a Buick but the steeper gears will get you into the power band much quicker, especially after shift points. If you plan on using a 28" tire than 3.73's are perfect. As for the rearend I don't know much about the one in your car but, if it is a 2.73 posi, I think you should have the bigger carrier and should be able to just change the ring and pinion.
